Empire EDR.9
Empire's "Extended Dynamic Response" flagship — a cartridge designed to sound identical in every preamp you own.
Overview
Empire's own advertising billed the EDR.9 as the first phono cartridge built to pass the company's listening tests on equal footing with its lab specifications — the pitch being that everyone else designed for the bench and left the sound to chance, a claim the company made in its period advertisements (High-Fidelity, May 1979, p.32).
That is marketing copy, and collectors should treat it as such. But the engineering underneath the claim is genuinely unusual, and it is the reason this cartridge still commands attention decades later.The heart of the EDR.9 is its L.A.C. — Large Area Contact — stylus, a profile Empire says was based on and named after E.I.A. Standard RS-238B. The design pairs a smaller radius with a larger contact area, yielding a pressure index of 0.9. Empire claimed this represented an improvement of almost six times the typical elliptical stylus and four times over the newest designs from several other cartridge makers. The practical upshot: less pressure on the vulnerable groove wall while extending bandwidth into the overtones and harmonic detail. Empire also fitted a patented 3-Element Double Damped stylus assembly that acts as a mechanical equalizer, suppressing the high-Q resonances typical of other stylus assemblies for a flatter response and reduced record wear.
The cantilever carries a mechanical equalizer inside the tube — an "Inertially Damped Tuned Stylus" assembly Empire says took over six years to refine. Its job is twofold: cancel the natural resonance of the cantilever tube and improve overall transient response, producing a stylus assembly with a mechanically flat frequency response. Empire rated the EDR.9's response from 20 Hz to 35 kHz with a deviation of no more than ±1.75 dB, and stated no other magnetic cartridge could match that figure. The pole rods are laminated rather than one-piece to reduce losses in the magnetic structure, flattening high-frequency response and lowering distortion. The EDR.9 also weighs one gram less than previous Empire phono cartridges, which Empire pitched as a match for the low-mass tonearms of the day.
The most interesting design decision is electrical. Conventional cartridges, Empire argued, change frequency response radically depending on the capacitance and resistance of whatever preamp they're plugged into — so their real-world response is "determined essentially by chance." The EDR.9's electrical elements were engineered to remain unaffected by normal variations in load capacitance or resistance, holding its smooth response and transient behavior across systems. Whether or not that claim held absolutely, it was a serious engineering goal at a time when most makers simply published a recommended load and left it there.
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